Renalase (RNLS) is a protein produced predominantly in the kidney, heart, skeletal muscle, testes and to a lesser extent in other tissues (Xu et al., 2005 J Clin Invest. 115 (5):1275-80 and Wang et al., 2008 Mol Biol Rep. 35(4):613-20). Two isoform variants of renalase have been described, Renalase-1 and Renalase-2. These two forms of renalase differ due to differential splicing of the final exon. Renalase has been described as a novel flavin adenine dinucleotide-containing monoamine oxidase with an activity that selectively deaminates the catecholamines epinephrine, norepinephrine and dopamine. A deficiency of renalase in the plasma of patients with end-stage renal disease, in comparison to healthy individuals, has been described. Catecholamines play a major role in the maintenance and modulation of blood pressure, including in disease, through effects on cardiac output and vascular resistance. The infusion of a recombinant form of renalase into rats caused a decrease in cardiac contractility, heart rate, and blood pressure. Patients with renal failure have been characterized with heightened levels of circulating catecholamines which correlate with hypertension and greater mortality through cardiovascular complications. Thus the protein renalase may play a role in the control and maintenance of catecholamine-induced changes in blood pressure and the deficiency of renalase observed in renal disease patients may be detrimental to outcomes.
A deficiency of renalase in the plasma of patients with end-stage renal disease, in comparison to healthy individuals, has been described. Patients with renal failure have been characterized with heightened levels of circulating catecholamines which correlate with hypertension and greater mortality through cardiovascular complications. Thus the protein renalase may play a role in the control and maintenance of catecholamine-induced changes in blood pressure and the deficiency of renalase observed in renal disease patients may be detrimental to outcomes. However, little is know about the role of renalase in cancer.
An essential feature of cancer is dysregulation of cell senescence and death. Renalase (RNLS) is a secreted flavo-protein that protects against ischemic and toxic cellular injury by signaling through the plasma membrane calcium ATPase PMCA4b to activate the PI3K/AKT, and MAPK pathways.
Skin cancer is a common human malignancy, and its incidence has been increasing in developed countries (Gray-Schopfer et al., 2007 Nature. 445:851-7; Lowe et al., 2014 Mayo Clinic Proceedings. 89:52-9; Lesinski et al., 2013 Future oncology. 9:925-7). Melanoma is the deadliest form of skin cancer, with low survival rates once it becomes unresectable (Lowe et al., 2014 Mayo Clinic Proceedings. 89:52-9). It is a molecularly heterogeneous disease and some of the key alterations in signaling pathways that participate in disease development and progression have been identified. The Ras/Raf/MEK/ERK and the PI3K/AKT signaling pathways play key roles in the pathogenesis of melanoma (Gray-Schopfer et al., 2007 Nature. 445:851-7; Lesinski et al., 2013 Future oncology. 9:925-7; Yajima et al., 2012 Dermatology research and practice. 2012:354191). Mutations in Ras, Raf, PI3K or PTEN (PI3K inhibitor) can lead to the sustained activation of ERK and AKT, which in turn promote cell survival and proliferation. Dankort et al. demonstrated this well with conditional melanocyte-specific expression of BRafV600E in mice, none of whom developed melanoma, however, revealed 100% penetrance of melanoma development when combined with silencing of the Pten tumor suppressor gene (Dankort et al., 2009 Nature genetics. 41:544-52). The elucidation of these pathogenic pathways has facilitated the development of specific inhibitors that target hyper-activated kinases. While these agents have proven effective in the treatment of selective groups of patients with metastatic melanoma, their beneficial actions are often short lived, hence the pressing need for the identification of additional therapeutic targets.
RNLS expression is markedly increased in melanoma tumors, and specifically in CD163+ tumor associated macrophages (TAMs). In a cohort of patients with primary melanoma, disease-specific survival was inversely correlated with RNLS expression in the tumor mass, suggesting a pathogenic role for RNLS. Inhibition of RNLS signaling using siRNA, anti-RNLS antibodies, or a RNLS derived inhibitory peptide significantly decreases melanoma cells survival in vitro. Anti-RNLS therapy with a monoclonal antibody markedly inhibits melanoma tumor growth in a xenograft mouse model. Treatment with m28-RNLS (also known as 1D-28-4), caused a marked reduction in endogenous RNLS expression, and in total and phosphorylated STAT3 in CD163+ TAMs. Increased apoptosis in tumor cells was temporally related to p38 MAPK mediated activation of the B-cell lymphoma 2 related protein Bax. Expression of the cell cycle inhibitor p21 increased and cell cycle arrest was documented. These results indicate that increased RNLS production by CD163+ TAMs facilitates melanoma growth by activating STAT3, and that inhibition of RNLS signaling has potential therapeutic application in the management of melanoma.
Improved methods for the detection of renalase in bodily fluids and tissues may aid in the diagnosis and prognosis of renal disease, cardiovascular disease and/or cancer. However, the validation of renalase as a relevant biomarker requires highly selective reagents for its detection. Antibody-based technologies are widely used for the detection of biomarkers. To date there have been only a small number of reagent antibodies raised against renalase with no to minimal characterization.
Pancreatic cancer is one of the most lethal neoplasms, causing approximately 330,000 death globally and 40,000 in the US (World Cancer Report 2014. WHO Press; 2014). Pancreas cancer is difficult to detect, and most cases are diagnosed at a late stage (Nolen et al., 2014 PLoS ONE. 9(4):e94928). Although there has been some progress in the use of chemotherapy of this cancer, the disease remains extremely resistant to all drugs therapies (Hidalgo et al., 2010 New England Journal of Medicine. 362(17):1605-17). The overall 5 year survival for individuals with pancreatic cancer is <5% (Hidalgo et al., 2010 New England Journal of Medicine. 362(17):1605-17), and additional therapeutic targets are needed.
The development of pancreatic cancer relies on the stepwise accumulation of gene mutations (Jones et al., 2008 Science. 321(5897):1801-6), some of which cause abnormal MAPK, PI3K and JAK-STAT signaling. Progression from minimally dysplastic epithelium to dysplasia to invasive carcinoma reflects the stepwise accumulation of gene mutations that either activate oncogenes (e.g. KRAS2), or inactivate tumor suppressor genes 9 e.g. CDKN2a/INK4a, TP53 and DPC4/SMaD4) (Hidalgo et al., 2012 Annals of Oncology. 23(suppl 10):x135-x8). Ninety-five, 90 and 75% of pancreatic tumors carry mutations in KRAS2, CDKN2a, and TP53, respectively. These mutations result in sustained and dysregulated proliferation that characterizes cancer growth. The mutational landscape and core signaling pathways in pancreatic ductal adenocarcinoma (PDAC) have been defined through a comprehensive genetic analysis of 24 advanced PDACs (Jones et al., 2008 Science. 321(5897):1801-6). These data indicate that most PDACs contain a large number of genetic changes that are primarily point mutations, and which affect approximately 12 cell signaling pathways.
That study also identified five hundred and forty one genes overexpressed in PDAC by at least 10 fold in 90% of the tumors. This included a 2 to 4 fold increase in the recently characterized protein, renalase (RNLS), in tumors or in tumor derived cell lines. RNLS, a novel secreted flavo-protein (Xu et al., 2005 J Clin Invest. 115(5):1275-80; Desir et al., 2012 J Am Heart Assoc. 1(e002634; Desir et al., 2012 J Am Soc Hypertens. 6(6):417-26; Li et al., 2008 Circulation. 117(10):1277-82) with NADH oxidase activity, (Farzaneh-Far et al., 2010 PLoS One. 5(10):e13496; Beaupre et al., 2015 Biochemistry. 54(3):795-806) promotes cell and organ survival (Lee et al., 2013 J Am Soc Nephrol. 24(3):445-55) through a receptor-mediated process that is independent of its intrinsic enzymatic activities (Wang et al., 2014 Journal of the American Society of Nephrology. DOI:10.1681/asn.2013060665). RNLS rapidly activates protein kinase B (AKT), the extracellular signal-regulated kinase (ERK), and the mitogen activated protein kinase (p38). Chemical inhibition of either ERK or AKT abrogated the protective effect of RNLS (Wang et al., 2014 Journal of the American Society of Nephrology. DOI:10.1681/asn.2013060665).
Accordingly, there exists a need for improved methods and compositions that bind renalase, such as antibodies, for the detection, diagnosis, prevention and treatment of diseases or disorders including renal disease, cardiovascular disease, and cancer. The present meets this need.